This study is part of the San Antonio Family Heart Study, the first comprehensive genetic epidemiological study of atherosclerosis and its correlates in Mexican Americans. Its goal is to detect and map new polymorphic genes that influence variation in susceptibility to cardiovascular disease in Mexican Americans. Because non insulin dedepdent diabetes mellitus and obesity are risk factors for cardiovascular disease and are common in this population, the pleiotropic effects of diabetes and obesity-related genes on quantitative correlates of cardiovascular disease will also be study. More than 40 extended families will be studied and a complete risk factor profile will be developed.